Enterobacteriaceae

Front 1

Enterobacteriacae family characteristics

Back 1

found in soil, water, vegetation and part of normal flora.

Front 2

genera of enterobacteria. based on what?

Back 2

biochemical properties, antigenic structure, nucleic acid homology.

Front 3

Salmonella, Shigella, Yersinia pestis are what?

Back 3

always pathogenic!!!!!!!!

Front 4

E. coli, Klebsiella pneumoniae, Proteus mirabilis

Back 4

normal flora, can cause opportunistic infections.

Front 5

Physiology of enterbacteriacae

Back 5

Gram - bacilli, major cell wall component is heat stable LPS, when motile, motile by peritrichous flagella, grow rapidly on common laboratory media.

Front 6

metabolic characteristics of enterobacteriaceae

Back 6

acid from glucose, oxidase negative, reduces nitrate, catalase positive.

Front 7

Which enterobacteriaceae ferment lactose?

Back 7

E. coli, Klebsiella, Enterobacter, Citrobacter.

Front 8

Which enterobacteriaceae do not ferment lactose?

Back 8

Proteus, Salmonella, Shigella, Yersinia.

Front 9

Which enterobacteriaceae has high resistance to detergent effects of bile salts?

Back 9

Salmonella

Front 10

Which enterobacteriaceae has a prominent capsule or diffusible slime layer?

Back 10

Klebsiella.

Front 11

What are the three major antigens of Enterobacteriaceae?

Back 11

O antigens, K antigens and H antigens.

Front 12

O antigens

Back 12

polysacchs in LPS, specific O antigens in each genus, cross reaction occurs between closely related genera

Front 13

K antigens

Back 13

glycocalyx, slime layer, heat labile, may interfere with O antigen detection, cross reaction with other bacteria in and out of family

Front 14

Flagellar H antigens

Back 14

heat labile, can be supressed or undergo antigenic variation "phase change"

Front 15

Endotoxin-shared by all enterobacteriaceae

Back 15

toxicity depends on lipid A component of LPS, released at cell lysis, responsible for systemic manifestations of gram - infection (high mortality rate) complement activation, leukocytosis, thrombocytopenia, disseminated intravascular coagulation, fever shock death

Front 16

glycocalyx

Back 16

protects against phagocytosis, interferes with binding of antibody to bacteria, poor immunogen, poor activator of complement.

Front 17

Iron sequestration in enterobacteriaceae

Back 17

iron important growth factor, free form scarce in body fluids, in host iron bound to proteins, bacteria counter by producing competetive iron-sequestering compounds (siderophores) with higher affinity for iron than host-binding proteins.

Front 18

Antibiotic resistance in enterobacteriaceae

Back 18

chromosomal B lactamase (klebsiella) resistance encoded extra chromosomally, on transferable plasmids

Front 19

E. Coli

Back 19

enterobacteriaceae that causes UTIs, neonatal meningitis, septicemia, gastroenteritis.

Front 20

E. coli general characteristics

Back 20

causes more than 95% of community acquired UTIs in women of child bearing age, major cause of gastroenteritis in developing countries, most infections except for neonatal meningitis and gastroenteritis are caused by endogenous strains.

Front 21

What are some specialized virulence factors in E. coli?

Back 21

adhesins and exotoxins.

Front 22

UTI's caused by E. coli

Back 22

most originate with strains from large intestine, contaminate the urethra, ascend into the bladder, may ascend to the kidney, ascending infection vs. hematogenous infection. Specific serotypes commonly produce: adhesins which prevent flushing and hemolysins which cause cytokine release and inflammatory response.

Front 23

Neonatal meningitis (caused by E. coli)

Back 23

infection with mother's GI flora, meningitis caused by group B strep is more common, 75% of strains involved possess K1K antigen.

Front 24

E. coli Septicemia

Back 24

usually originates from infections in urinary tract or abdominal cavity (intraabdominal infection caused by intetinal perforation-trauma, appendicitis with perforation diverticulitis with perforation.)

Front 25

Gastroenteritis-6 types caused by E. coli

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Enterotoxigenic, enteropathogenic, enteroinvasive, enterohemorrhagic, enteroaggregative, diffuse adherent

Front 26

Enterotoxigenic E. coli ETEC

Back 26

mediated by heat labile and heat stabile enterotoxins, (LT1 like toxin of V. cholerae with one A subunit and five B subunits)

Front 27

(ETEC) B subunits bind to which receptor and what do they do?

Back 27

The bind to the same receptor as the cholera toxin (Gm1 ganglioside) and allow the A subunit to enter the target cell.

Front 28

In ETEC what does subunit A do when it binds GM1 ganglioside receptor?

Back 28

ribosylates a membrane protein that regulates adenylate cyclase. The effect is to raise cAMP levels that lead to increased secretion of fluid and electrolytes.

Front 29

In ETEC what does the toxin STa do?

Back 29

binds to guanylate cyclase, leading to increased levels of cGMP, subsequent hypersecretion of fluids

Front 30

What are the symptoms of ETEC?

Back 30

secretory diarrhea developed 1-2 days after incubation; lasts for average of 3-4 days; travelers diarrhea, Montezuma's revenge; cramps, nausea, vomiting, profuse watery diarrhea.

Front 31

Enterpathogenic E. coli EPEC

Back 31

major cause of infant diarrhea in developing countries, specific o groups associated with newborn nurseries.

Front 32

Pathogenesis of EPEC

Back 32

Bateria attach to cells of small intestine, then effacement of microvilli, also called A/E histopathology (attachment/ effacement histopathology); diarrhea results from malabsorption caused by microvillus destruction.

Front 33

Enteroinvasive E. coli EIEC

Back 33

invade and destroy colonic epithelium (same as Shigella) starts as watery diarrhea with a small number of patients progressing to fever, cramps, blood and leukocytes in stool (dysentery), specific O serotypes, disease seen in developing countries.

Front 34

Enterohemorrhagic E. coli EHEC

Back 34

acid tolerant, low dose can cause disease, disease can range from mild diarrhea to hemorrhgic colitis with severe abdominal pain, bloody diarrhea and little or no fever.

Front 35

What is a major complication of EHEC occurring in 10% of children under 10 years old?

Back 35

Hemolytic uremic syndrome-acute renal failure, thrombocytopenia, anemia.

Front 36

Pathology of EHEC

Back 36

In the normal flora of bovines, most cases associated with consumption of undercooked ground beef or other beef products.

Front 37

EHEC Non bloody diarrhea after what happens?

Back 37

after bacilli attach to epithelium of terminal ileum, cecum, and colon (mediated by intimin) cytotoxin elaborated which mediates bloody diarrhea and abdominal pain, two related shiga toxins: Stx-1 and Stx-2 induce A/E lesions, encoded by lysogenic bacteriophages, lysogeny associated with over 50 o types, serotype 0157:H7 most commonly isolated

Front 38

Enteroaggregative E. coli EAEC

Back 38

cause of persistent watery diarrhea with vomiting and dehydration, infants, developing countries, stacked brick autoagglutination of bacteria-mediated by bundle forming fimbrae(plasmid encoded genes), bacteria characterized by mannose resistant aggregative adherence factor, adherence of bacteria to intestinal mucosa blocks fluid, nutrient absorption

Front 39

Diffuse adherent E., coli

Back 39

produces watery diarrhea in infants ages 1-5 years old, stimulates elongation of microvilli with bacteria embedded in cell membrane